This invention relates to electrical clamp connectors for electrical conductors. More particularly, the invention is directed to a clamp connector that can accommodate a wide range of conductor sizes but is particularly adapted to a middle range of sizes, and that further can accommodate insulated conductors, bare conductors or a combination thereof. An improved connecting means allowing higher real torque is provided to connect the connector halves about the conductors while retaining the threaded end of the connecting bolt entirely within the connector body.
Electrical clamp connectors are known in the prior art having two half portions of electrically insulating material with a plurality of lengthwise grooves therein, the grooves of the connector halves mating and enclosing electrical conductors when the connector half portions are bolted together. Opposing electrical bridging members in the connector half portions extend transverse to the grooves and have piercing teeth protruding into the respective grooves to pierce the insulation of the electrical conductors from both sides and thus create electrical "bridging" between separate conductors within the connector for purposes of splicing the conductors or providing a tap-off connection.
Prior art connectors commonly are fastened by one or more bolts passing through both connector halves and each being captured by a nut member positioned at the opposite side of the connector from the bolt head, the threaded bolt end generally extending through and jutting out the bottom of the connector. The bolt end will necessarily extend out the bottom of the connector since the bolt generally engages the nut while the connector halves are partially separated to allow insertion of the conductors into the connector; the bolt, upon being torqued to thereafter bring the connector halves together about the conductors, will pass through and beyond the nut and thus the adjacent connector half for a distance up to as much as an inch or so. However, the exposed bolt end can abrade and damage surrounding conductors in an electrical installation enclosure, as well as cut or injure an installer in an electrical installation enclosure and cause discomfort to an installer's hand when making a number of such connections at the same time. The exposed bolt end also occupies space in installation enclosures where available space is often very limited. Prior art bolt connection means further do not always provide a sufficient strength of connection, and are prone to failure through inadvertent over-tightening.
A new connector is disclosed in our co-pending U.S. patent application Ser. No. 733,630 filed May 13, 1985 wherein the threaded end of the bolt does not extend through the connector but rather is retained within a pre-threaded elongated metal insert encapsulated within one of the two connector half portions. The metal insert has a lower flange positioned adjacent the bottom of its connector half-portion and has an elongated and profiled portion internally threaded and extending upwardly from the flange into a smooth-walled tubular insulating pipe upstanding from the connector half portion. The bolt screws solely into the metal elongated portion of the metal insert when the connector halves are connected together, and the two connector halves are of essentially the same depth in a direction along the bolt axis. While this design has its advantages and will work with all sizes of conductors, medium to larger size conductors require the elongated and profiled portion of the metal insert to have thicker walls in order to avoid bending or fracture of the insert when the higher installation torques associated with larger conductors are applied. The cost of the thicker elongated metal inserts thus becomes significant.
An additional defect of exposed bolt prior art connectors, when used with bare wire conductors, is that the connectors do not provide adequate means to retain sufficient holding of the wires after the bare wires have undergone cold flow upon piercing by the teeth and also after the connector and its wires have been cycled a number of times through the high temperatures found in a bare wire connector environment. The holding power of such prior art connectors radically decreases because of such cold flow and temperature cycling.